<template>
  <div class="goods">
    <div class="menu-wrapper" v-el:menu-wrapper>
      <ul>
        <li @click="selectMenu($index,$event)" v-for="item in goods" class="menu-item" :class="{'current':currentIndex===$index}">
          <span class="text border-1px">
            <span v-show="item.type>0" class="icon" :class="classMap[item.type]"></span>{{item.name}}
          </span>
        </li>
      </ul>
    </div>
    <div class="foods-wrapper" v-el:food-wrapper>
      <ul>
        <li class="food-list food-list-hook" v-for="item in goods">
          <h1 class="title">{{item.name}}</h1>
          <ul>
            <li class="food-item border-1px" v-for="food in item.foods">
              <div class="icon">
                <img width="57" height="57" :src="food.icon" alt="">
              </div>
              <div class="content">
                <h2 class="name">{{food.name}}</h2>
                <p class="desc">{{food.description}}</p>
                <div class="extra">
                  <span class="count">月售{{food.sellCount}}份</span><span class="rate">好评率{{food.rating}}%</span>
                </div>
                <div class="price">
                  <span class="now">¥{{food.price}}</span><span class="old" v-show="food.oldPrice">¥{{food.oldPrice}}</span>
                </div>
              </div>
            </li>
          </ul>
        </li>
      </ul>
    </div>
    <shopcart :delivery-price="seller.deliveryPrice" :min-price="seller.minPrice"></shopcart>
  </div>
</template>

<script>
  import BScroll from 'better-scroll';
  import shopcart from 'components/shopcart/shopcart';
  const ERR_OK = 0;

  export default {
    props: {
      seller: {
        type: Object
      }
    },
    data() {
      return {
        goods: [],
        listHeight: [],
        scrollY: 0
      };
    },
    computed: {
      currentIndex() {
        for (let i = 0; i < this.listHeight.length; i++) {
          let height1 = this.listHeight[i];
          let height2 = this.listHeight[i + 1];
          // 如果height2没有下一个或者在区间内则返回i
          if (!height2 || (this.scrollY >= height1 && this.scrollY < height2)) {
            return i;
          }
        }
        return 0;
      }
    },
    created() {
      this.classMap = ['decrease', 'discount', 'special', 'invoice', 'guarantee'];
      this.$http.get('/api/goods').then((response) => {
        response = response.body;
        if (response.errno === ERR_OK) {
            this.goods = response.data;
            this.$nextTick(() => {
              this._initScroll();
              this._calculateHeight();
          });
        }
      });
    },
    methods: {
      _initScroll() {
        this.menuScroll = new BScroll(this.$els.menuWrapper, {
          click: true
        });
        this.foodScroll = new BScroll(this.$els.foodWrapper, {
          // 实时监听到位置
          probeType: 3
        });
        this.foodScroll.on('scroll', (pos) => {
          // 四舍五入并取绝对值
          this.scrollY = Math.abs(Math.round(pos.y));
        });
      },
      // 右侧对应到左侧菜单
      _calculateHeight() {
        let foodList = this.$els.foodWrapper.getElementsByClassName('food-list-hook');
        let height = 0;
        this.listHeight.push(height);
        for (let i = 0; i < foodList.length; i++) {
          let item = foodList[i];
          height += item.clientHeight;
          this.listHeight.push(height);
        }
      },
      // 左侧对应到右侧菜单
      selectMenu(index, event) {
        // 当不是自定义派发的事件的时候，直接返回，否则执行我们下面的逻辑
        if (!event._constructed) {
          return;
        }
        // 获取原生dom的节点
        let foodList = this.$els.foodWrapper.getElementsByClassName('food-list-hook');
        // 跳到对应下标的dom节点
        let el = foodList[index];
        this.foodScroll.scrollToElement(el, 300);
      }
    },
    components: {
      shopcart
    }
  };
</script>

<style lang="stylus" scoped>
  @import "../../common/stylus/mixin";
  .goods
    display: flex
    position: absolute
    top: 174px
    bottom: 46px
    width: 100%
    overflow: hidden
    .menu-wrapper
      flex: 0 0 80px
      width: 80px
      background: #f3f5f7
      .menu-item
        display: table
        height: 54px
        width: 56px
        padding: 0 12px
        line-height: 14px
        &.current
          position: relative
          z-index: 10
          margin-top: -1px
          background: #fff
          font-wight: 700
          .text
            border-none()
        .icon
          display: inline-block
          vertical-align: top
          width: 12px
          height: 12px
          margin-right: 4px
          background-size: 12px 12px
          &.decrease
            bg-image('decrease_3')
          &.discount
            bg-image('discount_3')
          &.special
            bg-image('special_3')
          &.invoice
            bg-image('invoice_3')
          &.guarantee
            bg-image('guarantee_3')
        .text
          display: table-cell
          width: 56px
          vertical-align: middle
          font-size: 12px
          border-1px(rgba(7,17,27,0.1))
    .foods-wrapper
      flex: 1
      .title
        padding-left: 14px
        height: 26px
        line-height: 26px
        border-left: 2px solid #d9dde1
        font-size: 12px
        color: rgb(147,153,159)
        background: #f3f5f7
      .food-item
        display: flex
        margin: 18px
        padding-bottom: 18px
        border-1px(rgba(7,17,27,0.1))
        &:last-child
          border-none()
          margin-bottom: 0
        .icon
          flex: 0 0 57px
          margin-right: 10px
        .content
          flex: 1
          .name
            margin: 2px 0 8px 0
            height: 14px
            line-height: 14px
            font-size: 14px
            color: rgb(7,17,27)
          .desc
            margin: 4px 0 8px 0
            line-height: 12px
            font-size: 10px
            color: rgb(147,153,159)
          .extra
            line-height: 10px
            .count, .rate
              margin-right: 12px
              font-size: 10px
              color: rgb(147,143,190)
          .price
            font-weight: 700
            line-height: 24px
            .now
              margin-right: 8px
              font-size: 14px
              color: rgb(240,20,20)
            .old
              text-decoration: line-through
              font-size: 10px
              color: rgb(147,153,159)
</style>

